School Suitability Modeling:
This lab aimed to explore the most suitability areas a school could locate given certain spatial criteria. After analyzing the specified criteria using ArcGIS tools and assigning weights to the criteria, a suitability map was created. This map can then be used to help decision makers best determine where a new school could be located.
The client specified four preferred criteria to determine the location for the school. The first influential factor was to locate the school on a flat terrain with a low slope value. The second influential factor is to locate the school close to recreational centers. The third preferred factor is to evenly distribute the location of the new school from the existing schools in order to prevent a clustering of schools within a close proximity of each other. The fourth criteria are to locate new schools on either agricultural or barren land. The other land types such as brush, forest, built up, water and wetlands are areas the client would like to avoid constructing near. Based on the four criteria, the client has assigned certain weights to the four factors. The client assigned a 40 weight to be close to a recreation center. A 25 percent weight was assigned to locate the schools close in even distance from each other. A 13 percent weight was assigned to locate the schools on current landuse. And the lowest weight, a 12 percent, was assigned to the criteria to locate on current landuse such as agricultural and barrenland. The weights are important to help us determine the criteria the client requires versus prefers.
In order to measure the four specified criteria, different ArcGIS tools were used to study the spatial characteristics from the provided data. The client provided us with four data sets to use: raster elevation data, raster land use data, vector data of recreation sites and vector data of school sites. When performing a site suitability analysis, the specified criteria must be ranked in order to help the client prioritize the needs for the analysis. In order to rank data, the reclassify tool was used. Each criteria was classified into three categories and then were ranked based on their priority. Landuse was ranked on a one to three scale. A ranking of one was assigned to the most preferred land such as agriculture and barren land and a ranking of three was assigned to the least preferred land – built up, water and wetlands.
To measure the elevation of the terrain, the slope tool was used. The output was then reclassified into three classes ranging from a one, meaning relatively flat land to a value of 3, meaning highly steep land. To measure the distance from other schools, the multiple ring buffer was used to analyze the locations where schools were located within 1.5 miles of each other, 3 miles of each other or 5 miles of each other. The client prefers to evenly distribute the schools from each other schools therefore the schools closer to each other were assigned a reversed ranking order. The ranking of 1 was assigned to the schools within a 5 mile distance from each other, while schools within a 1.5 mile buffer were assigned a ranking of 3. To analyze the distances between recreation centers, the multiple ring buffer was also performed. Three buffer distances were used to determine if recreation centers were a quarter mile, three-fourths of a mile or 2 miles away from each other. The results from the school and recreation center buffers were then converted to raster data in preparation of the weighted overlay tool. This tool was used to combine the results of the landuse, elevation, school and recreation center analysis. Certain weights specified by the client were factored into the analysis to produce a final suitability map.
Model builder view of the school suitability analysis procedure.
Results: The following map resulted from the site suitability analysis. A light orange color was used to signify areas of high suitability and a red color shows areas of low suitability. Based on this analysis, we would recommend for the client to locate a new a school in the high suitability areas. These areas are close to recreation sites as preferred by the client and are located a little further away from the other schools. These sites also have a relatively flat terrain and are located in agricultural or barren land. Therefore, we would recommend for the client to choose the sites demarked as “high suitability” to best meet the preferences of the client’s criteria.